How can I verify a GUID number ?

Dear SQL,

I need to SELECT something from a database that has a UNIQUEIDENTIFIER (GUID) field,

If the number is wrong (has some other than A-Z 0-9) than theASP page just freaks out and gets "error converting from a character string to uniqueidentifier"

How can I check that the GUID is OK before I SELECT ?
this is the number format:
{7A9B5F81-4936-4A31-B4E2-9168AAB75A0}

I tried to cast this "error" number with no successs:
"WHERE Deceased_ID = cast('"& "---4936-4A31-B4E2-9168AAB75A0" &"' as uniqueidentifier)"

Thanks in advance, Yovav.?? The string you're trying to cast is not a valid GUID, whats with the concats and the "--"? If a GUID is in the database then it will always be valid.|||I know it's not valid - that's the idea...

I'm getting a GUID as a parameter (using GET) and I want to avoid getting an error
if the user will change the GUID I'm sending to something illegal like "--+..."

The problem is that if I'm trying to SELECT some stuff WHERE someGUID = '" & givenGUID & "'
it will get a nasty error on the ASP page (error converting from a character string to uniqueidentifier)

I also tried to cast it into varchar(38) - which is working - BUT not if the GUID contains some illegal characters...

I guess I will have to write a function to validate GUID number - I could not find a function like that anywhere :-(|||Solved|||but GUID is a datatype so it will error if you try to put an invalid item into it, can't you rely on that?|||Solved