Switch on phone
Enter CWM
Maybe you have made a backup before flashing? Then restore.
If not: Wipe cache, dalvik cache, try to boot.
If won't work:
Enter CWM again, wipe cache, dalvik, reflash firmware (might take an older version)
Reboot
If won't work
Enter CWM
Clear cache, dalvik an all data
Flash firmware (last working version)
reboot
Don't know how to enter CWM on HTC, have SGS2, but use google .-)
Hope it will workout