not really, I just reinstalled windows XP, now instead of having the rundll32 message appear when I shut down, it appears when I start up, saying some module could not be found, otherwise it works fine.

No that would be a last resort.

The first thing to find out is what the module is that could not be found, to make sure it is not a system file that has gone missing, but really as I suggested a rogue malware file that adaware deleted.

The message should give the name, please post it if you cannot determine yourself whether it is a legitimate file.

If it is not a required file then there are a coupole of things you could try:

1. Look in the startup tab of msconfig to see if any items there have an entry in the command column that looks like it is calling rundll32.exe to load that module. The line might look like:

%SystemRoot%\system32\rundll32.exe C:\some path\modulename possibly followed by',' and some switches

or C:\Windows\System32\rundll32.exe modulename

or rundll32.exe modulename,.....

[As an example of a command line that uses rundll32.exe to open a module is:

rundll32.exe %SystemRoot%\System32\mshtml.dll,PrintHTML "%1"

which means 'use rundll32.exe to load mshtml.dll to print the html file']

2. Search the registry for modulename and delete any values that have it as part of its data.

to see startup tab of msconfig, click start, run, type msconfig, click OK. click startup tab

to search the registry, click start, run, type regedit, click OK. With the My computer icon at the top of the tree in the left pane of regedit highlighted,  edit menu, click find, type in the module name, check all three boxes, click find next. If it finds an instance to delete right click on the icon in the data column, click delete; press F3 to search for next entry if any.