This is normal. You can interrupt the timer. If the recording has started, press Stop. Then select Yes (if you pressed Stop on the remote). If the unit has not started the timed record, then press Timer Set. Then press Timer Prog to check the status or change the settings of the scheduled programs. Alternatively, you should be able to eject the DVD or access the Setup menu after pressing Timer Set. When you press Timer Set again, you will again lock the DVD part of the unit until after the last scheduled recording is finished (assuming non-repeating events). As I recall, the Timer Set button is on the remote, second from the left on the bottom row of buttons.
If you have tried the Timer Set button, check if your remote is working. One way to check if the remote is sending an IR signal is to take a picture of the front of the remote with a digital camera (a cell phone camera will work). This takes two people - one presses the button on the remote while the other snaps the picture of the front of the remote. If you see a glow in the photo, then the remote is working. It's possible that the IR sensor or the input board has failed. These can often be replaced. Looking at the board for the part number will give you the best odds of finding a replacement (google the number). A Toshiba substitute remote which will match all of the features can be obtained here: http://www.remotes.com/remotes/servlet/rs?a=Search&o=c&uid=0&m=DVR670&uuid=12986040989660
The manual for the DVR670 is available from Toshiba: http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/modelContent.jsp?ct=DL&os=&category=&moid=2805108&rpn=undefined&modelFilter=DVR670&selCategory=2797338&selFamily=2797342
. Click on User's Guide. If the above link is a problem, then try starting at the support home page: http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/home.jsp
. Click on Downloads and use the drop down menus (DVD & Blu-ray, DVD Recorders, DVR670).
I hope this helps.