China DOS Union

I use Windows XP Professional Service Pack 2. The disc is pirated, with the SP2 patch integrated. It has had lots of problems from the very beginning. Now I’ve found that in NTVDM (that DOS kernel under XP (virtual machine)), some (not all) programs cannot run normally. The symptom is: as long as it goes full screen, it hangs (the DOS program hangs). What is the reason? Is it a system problem?
A question off to the side: if it is a system problem, then after buying a new system disc, how can I install it so that the original system settings remain unchanged and there is only one system on the hard drive (since I’ve never done it before, this is a very newbie question).

Simplified Chinese:
Everybody please help. I bump it! Traditional Chinese:
大家幫忙。我頂！English:
Help me!Prop up!

The simplest solution to your problem is to find an XP SP2 installation CD that has no problems, then delete the original system and reinstall it. Of course, it’s not very likely that your original system settings can be preserved, but you can back up important settings and data first.