Congress' investigative agency, responding to complaints from around the country, has begun to look into the Nov. 2 vote count, including the handling of provisional ballots and malfunctions of voting machines.

The presidential results won't change, but the studies could lead to changes.

The Government Accountability Office (search) usually begins investigations in response to specific requests from Congress, but the agency's head, Comptroller General David Walker, said the GAO acted on its own because of the many comments it received about ballot counting.

GAO officials said the investigation was not triggered by a request from several House Democrats, who wrote the agency this month seeking an investigation. The effort, led by senior Judiciary Committee Democrat John Conyers of Michigan, was not joined by any Republicans.

Walker said in a statement that some of the election work is under way. The probe will cover voter registration, voting machine problems and handling of provisional ballots, which were given to voters who said they were eligible to cast votes although their names were not on the rolls.

He cautioned that the GAO cannot enforce the law if voting irregularities are found, noting that state officials regulate elections and the Justice Department prosecutes voting rights violations and election fraud.

Conyers said in an interview Wednesday that several House Democrats "want the widest, most impartial investigation that can be had. Whether they (GAO investigators) want to go as far as we want to go, we're not certain. We're at first base. Where do we go from here?"

The congressman said he plans to meet with Walker and key Republicans to see whether Congress should take action to improve election systems.

He said he would like the investigation to include allegations that insufficient numbers of voting machines were sent to some Democratic areas.

The study also should cover how election officials responded to problems they encountered, he said.

Thousands of complaints have poured in to Congress and appeared on Internet sites about problems with the elections, the Democrats said.

In make-or-break Ohio, where Bush won 20 electoral votes, voters cast 155,337 provisional ballots. They are under review by state elections officials, who count them if registration is confirmed. About 78 percent of the ballots counted so far have been deemed valid.

Meanwhile, election officials in two Ohio counties have discovered possible cases of people voting twice in the presidential election, and a third county found about 2,600 ballots were double-counted.

Groups checking election results have overwhelmed Ohio county boards of election with requests for information, and a statewide recount of the presidential vote appears inevitable after a pair of third-party candidates collected enough money to demand one.

Other examples of problems cited by Conyers and other House Democrats:

— In Columbus, Ohio, an electronic voting system gave President Bush nearly 4,000 extra votes.

— An electronic count of a South Florida gambling ballot initiative failed to record thousands of votes.

— In Guilford County, N.C., vote totals were so large that the tabulation computer didn't count some votes, and a recount awarded an additional 22,000 votes to Democrat John Kerry.

— In San Francisco, a glitch in voting machine software left votes uncounted.

— In Youngstown, Ohio, voters who tried to cast ballots for Kerry on electronic machines saw their votes recorded for President Bush instead.

— In Sarpy County, Neb., a computer problem added thousands of votes to the county total. It was not clear which presidential candidate benefited from the error in the overwhelmingly Republican state.