Very nice, good work Tihiy Do you know if this method leaves currently installed drivers in the Windows folder, or driver files get deleted (like when removing devices in safe mode) ?
For updates check http://windowsupdate.microsoft.com/ or the unofficial service packs available here. BTW have you tried to repair your current IE instalation before upgrading to IE6 ?
Open up the properties for you connection. There is "Multilink" tab there, just add your second modem and see what happens. You may need an additional account for your ISP (not sure about this since i've not tried it myself)
Sounds like a RAM problem to me. Check if the sticks are fitted well on their slots and run some memory tests if you can (MemTest or GoldMem would be fine)