Here's a cheat sheet of how to fix crashing ArcMap. An ArcMap "crash" is when ArcMap abruptly closes, or closes with a popup referencing an application error.
Stop going down the list when things are working again. Good luck!
- If you get crashes on one mxd or dataset the mxd or data may be corrupted. Copy your layers, start a new blank MXD, paste to the new data frame. If it's a complex MXD that would take a lot of time to rebuild from scratch, try to repair the mxd with MXD Doctor. Back up your data and try to rebuild a dataset that is making things crash.
- Is there an system resources issue? (full C drive, %TEMP% pointing to a non-existent folder, etc)
- Can another user log into your machine and successfully do the workflow without a crash?
If so, Reset your ArcGIS application profile (first, try a rename of Normal.mxt, then whole ESRI profile, then the registry)
- Make sure your display adapter drivers are up to date. This is a likely fix if ArcMap fails on startup when ArcCatalog starts up just fine. (One time I actually had to downgrade a very new display driver to get things working, but usually the most current is best.)
- Start ArcMap with the log file option. Maybe the output will give you a clue.
- Go to Add/Remove Programs - right click ArcGIS Desktop - Repair
- A full uninstall/reinstall of ArcGIS should be a last resort, unless it's time to update anyway.