Try these one at a time.
Please post back with the solution that resolved it for you.
1. Perform Disk Clean-up checking all boxes except "Compress old
files"
Start/All Programs/Accessories/System Tools/Disk Clean-up
2. Go to Internet Options in the Control Panel:
Delete Cookies
Delete Files (check box "Delete all offline content")
Clear History
3. Reboot, login to an Administrator account.
Double click My Computer.
Double click C drive.
Double click Windows file.
Double click System32 file.
Right click catroot2, click rename, type "catroot2old"
ENTER
Otherwise:
Start the Administrative Tools utility in Control Panel.
Double-click Services.
Right-click Cryptographic Services, and then click Properties.
Click Automatic for Startup type, and then click Start.
4. If Cryptographic Services is already set to Automatic, disable it,
reboot, then go back and set to Automatic.
Reboot
5. Start/Run
Type "msconfig" ENTER
Select "Normal Start-up"
Click OK, follow prompts and reboot
6. Start/Run
Type "cmd" ENTER
a.
Type "net stop cryptsvc" ENTER.
Type "net start cryptsvc" ENTER.
b.
Type "regsvr32 softpub.dll" ENTER.
Type "regsvr32 wintrust.dll" ENTER.
c.
Type "regsvr32 initpki.dll" ENTER.
Type "regsvr32 dssenh.dll" ENTER.
d.
Type "regsvr32 rsaenh.dll" ENTER.
Type "regsvr32 cryptdlg.dll" ENTER.
e.
Type "regsvr32 gpkcsp.dll" ENTER
Type "regsvr32 sccbase.dll" ENTER
Type "regsvr32 slbcsp.dll" ENTER
Close the box and install the patch.
7. Otherwise:
Check for missing/damaged System files:
Start/Run
Type "cmd" ENTER
Type "sfc /scannow" ENTER
Have Windows XP CD nearby.
Reboot when completed.