Error messages

After a crash I installed WindowsXP Home Edition from the CD. All seemed to
work properly. But when I tried to install PaintShop Pro 8 again, I got this
* Wrong sign in My Documents.
Installing NERO 9 this one:
* SetupX.exe: Critical Error in installation of NERO, Message: SetupX.exe:
Cant find UnitSetup--
A scan with Search and Destroy showed 2 missing files in C:\Windows: *
cmmgr32.exe and winnt32.exe
During an other session I got this:
* Acces Violance 0x00650078. Tried to read from 0xFFFFFFFF
Can any one help me?
With best regards, Peter