Browsers in OS X slow or not working while browsers running in Parallels are fine

Question

From day one, I had massive problems using first Safari and then Chrome in OS X. I would have to refresh ten times or more to get to a webpage. I was advised to create a new user and see if the problem persisted and it didn't. Browsing was perfectly fine. But that does not solve the problem. I need to use the browsers in my user profile, not in one that has not got any of my applications in it. I did rebuild my user profile from scratch, which took a lot of time and I just ended up having the same problems.
Then I purchased Parallels and installed Chrome in there. And bizarrely, it's ok there. Still not as quick as I would expect, but useable.
Another peculiar thing is the choice or router: I bought a very fast Belkin router because initially, I just had a TalkTalk modem/router that came with the broadband. It is very slow and since it is downstairs, it never managed to transmit fully to my office. So, I connected the Belkin to the TalkTalk via Ethernet and was hoping that I would now get better and faster wifi. And that does work for my iPhone, iPad and PC but not for the iMac under OS X. If I go back to my TalkTalk wifi, it does work with the OS X browsers, but it is slow due to weak signal.
I know this is getting confusing, so here is an overview:
                       browser in OS X          browsers in Windows 7 through Parallels
TalkTalk wifi      works, but slow            works, but slow
Belkin Wifi        hardly works at all        works and mostly very fast
Following from that, here are a number of statements that should be true:
1. It can't be hardware, since wifi works with the TalkTalk router and even with the Belkin through Windows 7
2. It can't be OS 10.7 in general, since it is working with the TalkTalk even though it does not with the Belkin
3. It can't be the Belkin in general, since the browsers are working through Windows 7
4. It can't be the positioning of either the routers or the iMac, since it works for both routers in certain configurations.
I can only assume that it is some setting in OS 10.7 that is in conflict with the Belkin router.
Now, I can obviously use the internet through Parallels or use the TalkTalk but that is not the point. I paid good money for both the iMac and the Belkin and I think I should be allowed to expect both to work with each other! Or shouldn't I?!?
Anyway, any suggestion would be gratefully received!

Answer 1

Please read this whole message before doing anything.
This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.
The purpose of this exercise is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login. Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode and log in to the account with the problem. The instructions provided by Apple are as follows:
Be sure your Mac is shut down.
Press the power button.
Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).
Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
Test while in safe mode. Same problem(s)?
After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.