I'd want to say that these questions are on topic as long as they involve hardware that is reasonably similar to typical consumer PC hardware or is applicable to consumer PC hardware or software.
For example, a question related to a kiosk or other PC-like embedded system running Windows Embedded Standard 7 would be on topic, but a question involving POS-specific features on a device running Windows Embedded POSReady 7 would be off topic. Questions on PC-like hardware running Windows Embedded Enterprise may also be on topic. Borderline cases, such as those involving software functionality found on PCs but on an embedded device, should be decided on a case-by-case basis.
Of course, questions on devices running Windows Embedded Compact 7 and Windows Embedded Automotive 7 are off topic, as they are not similar to consumer PC hardware.