my processor is pentium pro and 60mb of ram. most of the time it hangs and still i can move the arrow. what are the possible reasons of these things?

Unfortunately the problem has to do with the age of your PC. Software and websites are requiring more and more ram to run. You have 60mb which is going to struggle in any environment. I tried to run 128mb ram with xp on an old computer, the result was a brutally slow load time with everything. A ram upgrade is one option, but you may want to look into a newer system. The good news is you can get a reasonable pc for dirt cheap these days. I might even suggest a notebook for around $300 if money is an issue.