I checked a year or so, and there were complaints about W7 and compatibility with hardware and software when upgrading older computers. I'm thinking these have probably been dealt with now, and with the W7 XP mode there shouldn't be problems with my existing software.
I would doubt problems from a year ago have been corrected. Compatibility with legacy (old) hardware and software is NOT
a Windows or Microsoft problem - Windows 7 looks forward not back. The problems of the past would need to be fixed by the makers of the legacy products, not Microsoft - and most hardware makers dropped support for their legacy stuff long ago.
Understand XP's support for legacy hardware and software is a MAJOR cause for XP's poor security, for which MS was bashed relentlessly for the next 10 years. In fact, they are still be bashed for XP - even though the security programs were caused by badguys, not Microsoft or XP.
Sticking with XP is sticking with a 10 year old operating system designed to support legacy HW and SW from the DOS era. It is time XP be retired.
That said, I would not attempt to do that with a 5 year old system as clearly, that HW is XP era stuff. If you still wish to move to Win7 with this old HW, I would run the advisor again after you get your new RAM in.