My computer seems to be infected with some viruses. It gets hung easily, at startup, in the middle of keying in somthing. At times, it will suddenly go into sleep mode, and the screen blacks out. I need to keep re-booting, many times, before it may be used. Still, it gets hung now and then. Please help.

Is this a new problem? If so try a System Restore to a previous date. start All Programs | Accessories | System Tools | System Restore

The next best step would be to run a HijackThis log by our Pros in that section:

Please follow the instructions HERE & then post your log in a new thread in the Spyware, Adware, Viruses and HijackThis Logs section.
(Not in this section please).

If they do not find anything come back here and we'll see what we can do.