Quote:

What about doubling the "??"?

In KiX, the ? is reserved.

So, it should be -

'https://support.dell.com/ProductSelection.aspx??SvcTag='+$serno



Not quite right. Things like '@' and '$' and '%' are metacharacters which can be expanded inside strings and so need special attention. "?" is simply a keyword in the same way as "Break" or "Cls". When it is in a string it has no special meaning - at least not to KiXtart.