Problem with NEW H520 when installed new power supply & graphic card. Please help!

Question

My H520 was working perfectly and was running FAST..especially when rebooting. ( It was AWESOME!  )Then I installed a new power supply (Coolmax 400w) and a new graphic card (Sapphire Radeon HD6450) and then everything changed.  Now my computer is booting very SLOWLY and all the programs are taking a long time to load too.  I was getting a black screen for almost a full 2 minutes before the windows 8.0 screen would finally load up and then it hangs there for a few seconds and finally goes to the start screen in windows.  But BEFORE I installed this new hardware, when I would reboot, I would see the Lenovo splash screen come up for a few short seconds and then it instantly went to the windows welcome screen.  And even then I would barely have enough time to see the welcome screen before it instantly loaded into the windows start screen.  Everything would load up fast on the desktop too and we'd be good to go. It all took about 30 SECONDS. 
But now? It takes MINUTES to get everything going.   After it FINALLY loads up (it takes almost 2 full minutes now!), everything hangs up.  When you first click on the desktop, it takes a few seconds for all of the icons to pop up.  Before I loaded the new hardware, everything loaded up instantly.  I didn't even see the icons load because they were already there.  But now I have to wait for them to load up before I can even see them.  And it's like that with every program and web browser I try to use now.  Everything hangs up at first and then finally loads.  The programs work but they are sluggish.
So I uninstalled the new power supply and put back in the original 280w power supply and I took out the graphic card but it did no change.  The machine is STILL running slow on everything it does and booting very slowly.
I have seen this problem mentioned elsewhere about Lenovo computers but there is never a solution.  Please help!  It took me a long time to save up for this computer and I have been babying it ever since.  I will never be able to afford a new one or pay for tech repair.  I need to fix this!    I was so thrilled with this computer before the hardware upgrade. This is devastating to me that it is working so poorly now when all I was trying to do was upgrade it a little bit.     Now it's performing horribly and it's only 6 months old. 
I ran a four hour test on the hard drive and it is fine.  I ran all the system clean ups, optimizations, registry cleanups, windows disk cleaner, defragger and virus scans. Nothing is showing up as not working but there is CLEARLY a problem.  It was never this slow.   And why is it STILL acting this slow even after I uninstalled all of the new hardware that made it start acting this way and went back to the original setup?
I'm trying to run a memory test on it now but the BIOS will NOT allow me to select another drive to boot from so I can't boot from the flash drive or CD drive to run the memory test.  I have NO IDEA what to do next and I am starting to pull my hair out in frustration.
Please, is there anything that can be done to make it better again?
Any help would be HUGELY appreciated.    Thank you!
Sincerely,
Jennifer

Answer 1

I totally give up!!  I restored everything to the ORIGINAL state with drivers AND hardware and STILL everything is not working properly like it was BEFORE the upgrade.
So this has been the WORST experience with Tech support EVER!!  I have spent DAYS on the phone for HOURS with these technicians and nobody seems to know what they are doing.  They put me on hold every 10 minutes and are gone for 10 to 15 minutes and when they come back, they seem all set on a new solution but when you ask them questions about it, they have NO CLUE how to answer and then they put you on hold again.  Nothing gets solved and after HOURS on the phone, I just tell them to stop because we are getting no where but running around in circles that make no sense.    THIS A NIGHTMARE!!
So I totally gave up on being able to upgrade this machine.  To any future buyers, I STRONGLY recommend you do all upgrading BEFORE you get it home for the first time.  Make sure you have your power supply and graphic card INCLUDED before you bring it home or you're mostly likely going to have a NIGHTMARE upgrading it later.    Technical support is a HORROR STORY and expect to be WAITING for LOOOOONNNNG periods of time both ON THE PHONE and ONLINE and probably ending up with NO SOLUTION in the end. 
I've VERY upset with how this turned out!!  I'm just gonna have to deal with the fact that my computer is permenantly messed up and NOBODY AT LENOVO knows how to fix it.    So I'm stuck. 
I decided to send back the new power supply and the new graphic card because of this nightmare with tech support.  I put everything back to the way it was when I bought the computer and it is STILL acting up!!  I just want to revert it back to factory settings .. INCLUDING THE BIOS... but Lenovo said I have to send the WHOLE computer back to them to do that.  All I can do from home is restore from a point in the hard drive and that's not enough.  I need a TOTAL CLEAN INSTALL.  Everything needs to be wiped out and reset, not just restored to a previous restore point.  I've done this multiple times and all it does is erase all the programs and stuff I put on the computer.  The drivers and other codes are still the same.  And then bugs come up and things get all wonky.  I NEVER HAD THIS PROBLEM BEFORE I TRIED TO UPGRADE IT!!
I am NOT comfortable with Lenovo's "solution". I do NOT want to send my computer back to them for them to reset it with factory disks ESPECIALLY when they stated that they are NOT responsible for any damage in transport or otherwise. I have to buy extra packaging to make sure it gets there safely. They told me to use the original box and packaging, that is the only way they can be sure it will get there safe.  Who has the original stuffing SIX MONTHS LATER?!?! I don't want to be sending my computer across the country to get jostled all over the place and have that add to the slowness of the hardware because it was jostled.
Can't I reset it from home?  Can they not send ME the disks instead of me sending my whole computer to them?
I'm so incredibly frustrated with this.  I hope somebody answers quickly and that I don't have to wait DAYS to get a response again. 
I absolutely LOVED my Lenovo computer!  And then I tried to upgrade it.  BIG MISTAKE!!  Now everything is totally messed up and Lenovo's customer support for technical problems is HORRID!!
Somebody please help.  This is driving me crazy with frustration and totally breaking my heart.  It took me a VERY long time to save up for this computer and it was my most loved possession.  It was a reward for a lot of hard times and now it's all broken and acting slow.  And it's only 6 months old.  
Is there a solution to this very frustrating problem?
I just want it to go back to the way it was before. 
And is there a very low cost KNOWN TO WORK WITH THIS MACHINE upgraded graphic card and power supply?  Is there a very specific brand and make?  If so, could you let me know what it is in case I try to upgrade it again someday?
Thank you for your time and for reading this! 
Please have a FANTASTIC day today!!
~Jennifer~