Windows XP is waaaaay past its end-of-life so – NO.
Windows Vista might work but I haven’t tried it for many years.
tvCAD rarely uses more than a few hundred MB of RAM in general usage (usually less than 200MB), although a cable schedule with ~ 100,000 cables used ~ 800MB momentarily while it was creating the spreadsheet. tvCAD will run at the pretty-much the same speed as everything else on your computer.
The installation is around 300MB, depending on which part of Windows you ask.
You don’t need AutoCAD, it is built into tvCAD. The AutoCAD part is 90% of the size of tvCAD. It’s AutoCAD 2018 so tvCAD can ready any drawing you can read in the latest version of AutoCAD.
You don’t need Excel to create cable schedules, it is built into tvCAD
You don’t need SQL-anything, the database engine is built into tvCAD.
You don’t need a DBA, there are no database administration tasks, it just works.
If you want to see and query the database, go right ahead! It is a standard SQLite database
tvCAD runs on the .NET 4.6 framework. The installer will let you know if it is missing.