Windows – Possible registry fix for a “Not enough memory to run Microsoft excel” error

Background:

The other day, on my Microsoft XP laptop, I started getting "Not enough memory to run Microsoft Office Excel. Please close other applications and try again." when trying to start Excel 2007. Also, all other Office applications refuse to start with various error messages. I tried the repair option from the install image and also uninstalled/reinstalled but the error persist.

I found this superuser thread with a link to a suggestion that this is a user account error in the registry

It says:

"I am aware of the error you are getting, in order to get rid of it you will have to delete below key
HKLM\Software\Microsoft\Windows\CurrentVersion\Installer\UserData\SID of the affected user>
You can follow below steps for doing that.
Go to start > run > type "regedit" without quotes and click on ok.
Navigate to above registry key and delete it.
Make sure that you are backing up current registry to be at safer side, best of luck."

Just to check if this could be a user account error, I set up a new test account on my laptop and using this account Office works as usual.

So, the proposed registry fix is to delete
HKLM\Software\Microsoft\Windows\CurrentVersion\Installer\UserData\SID of the affected user>

This registry key holds loads of sub folders and keys and I'm feeling reluctant to remove it without knowing more of what it's for and possible implications.

So are there any registry gurus out there who can tell me wether it's safe to remove this key to fix this Office error?

Edit:
Type wmic useraccount get name,sid in your command prompt to find out your SID.