If it's any help, the test emphasized the following when I took it -
1) NTFS and Share permissions as they relate to users and groups and to
each other. Study these as if you are writing a book on them. They were
as prevalent on the 70-270 exam for me as they were on the 70-290.
2) RIS installs (Risetup.exe, RIPrep.exe, Rbfg.exe), Sysprep, all CD
based installs via command line switches (i.e. Winnt32 /unattend)
3) Profiles (roaming, mandatory, local)
4) Print servers - managing, configuring printer pools, troubleshooting
queues and setting priority for jobs
4) Any and all Remote Desktop / Remote Assistance scenarios you can
think of.
5) Files and Settings Tranfser wizard and USMT (scanstate, loadstate)
6) Rolling back drivers, driver signing policy (warn, block, ignore)
and booting under different hardware profiles
7) IIS running in Windows XP. Configuration, troubleshooting,
limitations.

Dynamic disks in XP, when you can and can't defrag disks and how
disk quotas work
9) System Monitor-ing / counter logs / trace logs / alerts
10) When to perform an ASR (hardly ever), log onto Recovery Console
(occasionally), boot in Safe Mode (sometimes), roll back to a previous
System Restore point (many times) or just simply boot with a Last Known
Good Configuration (most of the time).
Now, don't just study these things and ignore everything else... but if
you study these items and have a solid grasp of XP installation,
administration and support you should pass the test without any
problems.