system restore fix or return to original application issues

Rather than going into details;I am looking at sys restore as an option.I continue to get prompts re-sych sys clock from MS to debug.Most of the errors are to application;with last being the sys clock.The only changes I made recently was changing pdf readers Adobe Reader to Foxit reader;the reason was update mgr conflict.I would like to fix the problems myself without the sys restore however am not that experienced.Can I do it or not? I use xp home. thanks jerry