If you're getting error 1053 (iirc) with ArcSDE, the deal where it complains, "the service did not respond to the start request in a timely fashion" or some such, double check your license server settings.

Step one, run the following command at a command prompt (with sample results):

sdeservice -o list

SDE service Information
Service Name: ArcSde Service(esri_sde)
Service SDEHOME: C:\arcgis\ArcSDE\sqlexe
Service License Server: @BOX1
Service Datasource: SOMEBOX

Let's say you don't want to use BOX1 as your license server... fire up regedit and search for the LICENSE_SERVER key. Change its value from @BOX1 to @BOX2 or whatever your license server is. This oughta fix things if your old license server doesn't have the correct information, has moved, or is now, say, behind a firewall. And don't forget to keep the "@" in front of the license manager server's name.

Here endeth the very industry specific lesson.