1.   But British investors could not trade for much of the day because of an unexplained technical problem that crippled the London Stock Exchange.

2.   But industry observers say such incidents could be prevented if chipmakers published their bug lists, so designers would have a better chance of solving unexplained problems themselves.

3.   She said an unexplained problem still under investigation caused the substation to shut down.

4.   A Russian military satellite was placed in orbit late Monday in a launch delayed for several hours by unexplained technical problems, Russian news agencies reported.

5.   A sweeping power outage caused by an unexplained technical problem left nearly all of Iran without electricity on Sunday, an Energy Ministry official said.

6.   But because of unexplained technical problems, the transmitter was silent at nightfall.

7.   The U.N. committee agreed to a similar arrangement last February but the deal fell through because of unexplained problems with the Russian supplier.

8.   Unexplained problems delayed the start of peace talks between representatives of Afghan President Burhanuddin Rabanni and the Taliban militia of religious students on Sunday, officials said.