Internet Explorer won't connect

i was having issues with my pc crashing to a restart. at first i thought it was a malware/virus issue so i began a thread in the malware forum. after about a week of scans without any indication of threats i'm having problems connecting to the internet using IE8 (double click IE and a "cannot display webpage, and programs like malwarebytes cannot connect to the internet to install updates, etc), slow loading times upon starting pc (it can take roughly 10-15 minutes before i could open my computer, IE, and close ATI multimedia center toolbar), and program freezes (when trying to close ATI multimedia center toolbar it would freeze and take a while to exit, using media player would stall and lock up, and using a windows task manager would freeze).

currently im using another pc to connect to the internet on my home network so i know it's isolated to the problematic pc. i was instructed to get some guidance on how to remove SP3 so i can complete a sfc /scannow because the last mod believed my problems were windows related.

http://forums.majorgeeks.com/showthread.php?t=242580

MY PC
Intel Pentium 4
3.0GHZ
Windows Home XP service pack 3
2 GB Ram
32 Bit
I have installed a new CPU (exactly the same as the original)with after market fan roughly 3-4 years ago.
I have a newer power supply (corsair) purchased last December (2010)
There arent any bulging capacitors and the PC has been sprayed clean and have plenty of air flow.

Thank you for taking the time to help me

 

I think in some cases you can't remove sp3. However you should be able to reinstall it.

Can you try the below?
http://majorgeeks.com/Microsoft_Windows_XP_Service_Pack_3_d4323.html
See the download links under this icon: http://forums.majorgeeks.com/chaslang/images/MGDownloadLoc.gif