设计器忽然不显示图形化编程了

昨天对程序作了一下改动，不知怎么的设计器模式下就不显示了，只是显示如下一堆乱码，请问怎么解决？
<html><head><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8"><title></title><style>.ErrorStyle { font-family: tahoma; font-size: 11 pt; text-align: left}.DetailsStyle { font-family: tahoma; font-size: 10pt; text-align: left;text-indent: 0; word-spacing: 0; line-height: 100%; float: left; margin-top: 0; margin-bottom: 0}.StackStyleVisible { font-family: tahoma; font-size: 10pt; text-align: left; margin-left: 20; text-indent: 0}.StackStyleHidden { display:none; font-family: tahoma; font-size: 10pt; text-align: left; margin-left: 20; text-indent: 0}</style></head><body><DIV class="DetailsStyle" width="100%"><table border="0" width="100%" id="table1" height="100%" cellspacing="0" cellpadding="0"><tr><td height="40" bgcolor="#FF9999" width="8%" style="letter-spacing: 0" align="center"><img border="0" src="C:\Users\lenovo\AppData\Local\Temp\1568C3F.tmp" width="35" height="35" alt="ErrorImage" ></td><td height="40" bgcolor="#FF9999" width="91%" style="vertical-align: top; letter-spacing: 0" align="left"><b><font size="2" face="Arial" fontsize="70%">鍔犺浇璁捐鍣ㄦ椂閬囧埌涓€涓垨澶氫釜閿欒銆傝繖浜涢敊璇湪涓嬮潰鍒楀嚭銆備竴浜涢敊璇彲閫氳繃閲嶆柊鐢熸垚椤圭洰鏉ヤ慨澶嶏紝鑰屽彟涓€浜涢敊璇垯闇€瑕佹洿鏀逛唬鐮併€?/font><font size="2" face="Arial"></font></b></td></tr><tr><td colspan="2" align="left" valign="top"><DIV id="div1" class="ErrorStyle" width="100%"><span style="font-weight: 600"><br>鎵句笉鍒版枃浠?'D:\Program Files\Microsoft Visual Studio 8\Common7\IDE\data.mdb'銆?</span><br><a href="" id="details0">闅愯棌</a><font color="#0000FF">&nbsp;&nbsp;&nbsp;&nbsp</font></DIV> </td> </tr> <tr><td colspan="2" align="left" valign="top"><DIV id="div20" class="StackStyleVisible" width="100%"><br>   鍦?System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection)<br>   鍦?System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject)<br>   鍦?System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup)<br>   鍦?System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)<br>   鍦?System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)<br>   鍦?System.Data.OleDb.OleDbConnection.Open()<br>   鍦?BooksBox.DataOperation.GetDataReader(String selectstr)<br>   鍦?BooksBox.BookUpdate.updateEntry.Start()<br>   鍦?BooksBox._Controls.HistoryList.HistoryList_Load(Object sender, EventArgs e)<br>   鍦?System.Windows.Forms.UserControl.OnLoad(EventArgs e)<br>   鍦?System.Windows.Forms.UserControl.OnCreateControl()<br>   鍦?System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)<br>   鍦?System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)<br>   鍦?System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)<br>   鍦?System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)<br>   鍦?System.Windows.Forms.Control.CreateControl()<br>   鍦?System.Windows.Forms.Control.ControlCollection.Add(Control value)<br>   鍦?System.Windows.Forms.Form.ControlCollection.Add(Control value)<br>   鍦?System.Windows.Forms.Design.ControlDesigner.DesignerControlCollection.Add(Control c)</DIV></td></tr></table></div></body></html>