Slow Response Time After Converting DB From SQL 6.5 To 7.0

We did an in place convertion of our data base from MS SQL Server 6.5 to 7.0.
Our application is much slower now on SQL 7.0. Any idea why?
The following is a sample SQL statement that runs quickly on SQL 6.5 and takes a long time on SQL 7.0 I also attached the query plans from SQL 6.5 and 7.0.




SELECT Person_Name.PerNam_Person_Name_PK ,
Person_Name.PerNam_Row_Status ,
Person_Name.PerNam_Last_Name_Sndx ,
Person_Name.PerNam_Last_Name ,
Person_Name.PerNam_Name_Suffix ,
Person_Name.PerNam_First_Name ,
Person_Name.PerNam_Name_Prefix ,
Person_Name.PerNam_Middle_Name ,
Person_Name.PerNam_Event_Person_FK ,
Event.Evn_Event_Nbr ,
Event.Evn_Event_Type ,
Event_Person.EvnPer_Last_Name ,
Event_Person.EvnPer_First_Name ,
Event_Person.EvnPer_Middle_Name ,
Event_Person.EvnPer_Name_Prefix ,
Event_Person.EvnPer_Name_Suffix
FROM Person_Name , Event , Event_Person
WHERE (Person_Name.PerNam_Agency_ID = "CL")
AND ( Person_Name.PerNam_Event_Person_FK = Event_Person.EvnPer_Event_Person_PK )
and ( Event_Person.EvnPer_Event_FK = Event.Evn_Event_PK )
and (Person_Name.PerNam_Person_Name_PK = 0 or ( Person_Name.PerNam_Event_Person_FK = 581541) )
and ( Person_Name.PerNam_Row_Status <> "D" )




Query plan in SQL 6.5

SQL Server Execution Times:
cpu time = 0 ms. elapsed time = 31250 ms.
STEP 1
The type of query is INSERT
The update mode is direct
Worktable created for REFORMATTING
FROM TABLE
Person_Name
Nested iteration
Index : PK_Person_Name
FROM TABLE
Person_Name
Nested iteration
Index : PerNam_Event_Person_FK
FROM TABLE
Person_Name
Nested iteration
Using Dynamic Index
FROM TABLE
Event_Person
Nested iteration
Index : PK_Event_Person
TO TABLE
Worktable 1
STEP 2
The type of query is SELECT
FROM TABLE
Worktable 1
Nested iteration
Table Scan
FROM TABLE
Event
Nested iteration
Index : PK_Event
SQL Server Parse and Compile Time:
cpu time = 0 ms.
Table: Person_Name scan count 2, logical reads: 6, physical reads: 5, read ahead reads: 0
Table: Event scan count 0, logical reads: 0, physical reads: 0, read ahead reads: 0
Table: Event_Person scan count 0, logical reads: 0, physical reads: 0, read ahead reads: 0
Table: Worktable scan count 0, logical reads: 0, physical reads: 0, read ahead reads: 0
Table: Worktable scan count 1, logical reads: 1, physical reads: 0, read ahead reads: 0

SQL Server Execution Times:
cpu time = 0 ms. elapsed time = 62 ms.



Query plan on SQL 7.0

SQL Server parse and compile time:
CPU time = 431 ms, elapsed time = 535 ms.
.................
Table 'Event'. Scan count 1, logical reads 3, physical reads 3, read-ahead reads 0.
Table 'Event_Person'. Scan count 1, logical reads 6, physical reads 5, read-ahead reads 0.
Table 'Person_Name'. Scan count 1, logical reads 4588, physical reads 2, read-ahead reads 4092.

SQL Server Execution Times:
CPU time = 7921 ms, elapsed time = 13519 ms.

SQL Server Execution Times:
CPU time = 0 ms, elapsed time = 13781 ms.