At the very last resort you could 'upgrade' to Windows 7, but the issues you describe may just need work to resolve.
You say it is running sluggishly but then refer to a browser home page, so is the problem with the browser, or with the computer in other ways?
If it is just the browser, which browser are you using? If just Internet Explorer 8, (IE8), I would hazard a guess that it has bad or corrupted Add-ons installed.
A quick test. Goto Start > All Programs > Accessories > System Tools and select "Internet Explorer (No Add-Ons)". This will open IE8 in it's 'Safe Mode' without 3rd party toolbars, add-ons, etc. Can you use it now without problems? In this mode many web sites may not display properly, but since this is only a test that doesn't matter.
If IE8 works faster in this mode, then the problem is Add-ons and you can start testing which add-ons by opening IE8 normally and go to Tools > Manage Add-ons, and try elimination tests.
The other thing of course is viruses and malware. You don't say about that so all we can say is you need a Firewall, an Anti-virus scanner, and a couple of anti-malware scanners.
Finally, I would recommend you download and install and then use another browser, like Firefox, Opera, Safari, and so on. It helps to keep malware to a minimum.
I have a Dell Studio desktop Q8200 (2.33 GHZ) WITH 4 GB of DDR2 SDRAM at 800 MHz. Hard drive is 500 GB. It is running Vista OS and is up-to-date with all the updates. It was purchased in May 09. Of course the 1 year warantee has expired.
For the last couple of months it has been running extremely sluggishly...takes forever for my home page to come up, and links clicked from the home page take a while to load...even solitaire takes a while to load.
I know the computer should be diagnosed hands on, but...in your opinions, based on experience...is this a computer issue or a Vista issue? I could buy Win 7....should I? or get a whole new computer? It is just used for basic surfing, emailing, word processing. Thanks.