Not sure you needed to re-install

i would have just checcked :
Program Files > Administrative Tools > Internet Information Services > Expand Computer Name > Expand Websites > Right Click on eManager Website > Properties > Selct ASP.Net tab > ensure v2.0.50727 is selected.
Windows updates cause blank entry here and you need to re-select.
If this does'nt work you may want to turn off freindly messages in IE to give more info on error.
Hope this helps