If that's the case, then it probably won't work in "Safe Mode". Try using a standard PS2 mouse when in "Safe Mode". You should be able to access System Restore from Safe Mode then.
I would sure help if we knew which operating system you're using. XP or ME?
The Ptsnoop.exe program is probably the one which is related to your dial-up modem. If you can click on "Start-Run, type "msconfig", then click on the "start up" tab. If "Ptsnoop.exe" is listed there, try UNCHECKING it, then restart the computer into "normal" Windows.
Hope this helps.
My pc started up with safe mode on my home page, also a box popped up stating ptsnoop caused error in mmsystem.dlle prompting to restart pc, when I did the same safe mode with the mouse cursor still not operating,appeared, keyboard is ok, but I am unable to reach system restore to try going back a few days, can anybody help, thanks.