Solved Microsoft Commerce 2007 Problem!

Ahoy there, this is my first post in this (very useful) forum.
I was wondering if you could solve the problem for me, because im helpless.
Using operation system: Windows Xp Sp2, Pentium D 3.00GHz, 0.97GB Ram, the problem is with Microsoft commerce catalog and marketing manager, lately it became extremely slow, opening a category sometimes takes longer than 5 minutes, etc (everything is very slow), and i have contacted Microsoft support, they checked and their answer was the everything is OK on the server and they see no problem from their side, which mean there is something wrong with my PC,OS, i do not know, maybe some spy ware (although i have checked and found none).
*I can't tell if it's connected somehow, but the FTP is also very slow.
I will gladly provide with any additional details, you just tell me what you need to know.

*additional info - when using mobile modem, both commece and FTP go faster (still slow, but faster).

Any help will be appreciated, thanks a lot in advance.

Alex.