PLEASE HELP!! iMac not working

Question

Help required!!!
I'll start from the beginning,
Last Friday I had an issue with accessing my wireless network from my iMac, I called my ISP (Virgin Media) who asked me to hard wire the mac to the router, I had to move the mac from its desk to next to the router, so shut down and moved it to where the router was in another room. Virgin made some changes to the router, and I still couldn't access the router wirelessly, virgin asked me to shut the mac down and restart, on rebooting I got the white screen with the apple logo and then it shut it self down I tried this a couple of times with virgin on the phone, after a couple of attempts they said it was obviously a problem with the mac and not with them and said I should call them if I get the mac working and the wireless still doesn't work. I was left very worried as the mac was now worse than when I called them, luckily I have an iPad so was able to get online to diagnose the problem with the mac.
I moved the mac to back to its original place on the desk and started to try and fix it!! thankfully I have my files backed up. the following is a list of things I have tried over the last 4 days and my results.
1. Reset the SMC, no use same problem.
2. Restarted the mac using the leopard installation discs, first of all the disc said that os installed wasn't correct, so went to disc utility to view problems with the hard disc, the verify disc diagnosed a invalid node structure. Looked this up online and the majority of forums were recommending a erase and install, so I erased the HDD, and as I had seen somewhere else online partitioned the drive into a start-up disc and another for storing files etc... (not sure if this was needed, but I did it anyway, and it wasn't the first time I had seen this advice). After the erase, I re-checked the disc using verify disc, hooray no problems!! So I thought!!
3. re-installed leopard, seemed to install ok, once in, I did another disc check all ok, so I started to re-install my software iLife '09, iWorks '09, all working ok. Updated iTunes to the latest version, started to import over from backup, my music, videos etc.. and iTunes stated that it need Safari 3, so updated quite a bit, leopard 10.5.8 combo update, security updates, iLife updates etc... including Safari 3.
4. Installed updates and restarted the mac, on reboot the computer went to a blue screen and stuck there, tried rebooting a couple of times, reset the PRAM as suggested on a forum, No Joy!!
5. followed item C on the following page http://support.apple.com/kb/ts1545, didn't work!! So Restarted using the installation disc, and carried out an archive and install, all seemed to be ok until I started up and logged on now Spotlight keeps crashing, to the point it doesn't actually load anything!!!
I know there is a lot here to get you head around, and believe me I've tried to keep this as concise as possible.
I would appreciate any help, as I'm getting quite frustrated... I'm snowed in can't take it to a Genius Bar...
MAny Thanks in advance James Lyall

Answer 1

Hi - Well, you've certainly had a good go at trying to fix things. Bad luck that you still have problems.
Just to throw in a couple of other things you could try, have you tried a Safe Boot
http://support.apple.com/kb/ht1455
Also 'repair permissions'? If you manage to boot from the Macintosh HD: Utilities>Disk Utility and select Macintosh HD on the left and click 'repair permissions'.
Not sure about the merits of partitioning the HD as you describe. If you need to re-install again maybe worth reverting to a single partition so that the drive is like they leave the factory, as it were.
Good luck.