Question : OS install Mode enabled - How do I disable it

After a memory problem I now get the following message: "Alert! OS install mode enabled.  System memory limited to 256 mb"
How do I disable this.    Several post ob Google said it was in systems setup, I could not find it.
This is a Dell 4700, Running XP, with 1.5 G memory installed.
Thanks

Answer : OS install Mode enabled - How do I disable it

When I got the message the next time I told it to default to defaults, this fixed the issue